Disc recording/reproducing apparatus and disc recording/reproducing method

ABSTRACT

In a disc drive device ( 10 ) described as a specific embodiment of the present invention, AC 0  to AC 14  of ADIP cluster address are associated with address bits AU 6  to AU 20  of an address unit. On the basis of 8-bit sector address on the lower side of cluster address arranged in ADIP address of a conventional MD, 0/1 representing sector address FC to 0D of a former-half cluster and sector address 0E to 1F of a latter-half cluster of a sector of a next-generation MD( 1 ) is associated with address bit AU 5  of the address unit. To a part ( 110 ) of 4 address bits AU 4  to AU 1  below this, 4 bits representing individual parts obtained by equally dividing one recording block by 16 are allocated. Thus, a higher-density data volume can be handled without causing any inconvenience while utilizing an existing recording format.

TECHNICAL FIELD

[0001] This invention relates to a disc recording/reproducing device anda disc recording/reproducing method.

[0002] This application claims priority of Japanese Patent ApplicationNo.2002-098047, filed on Mar. 29, 2002, the entirety of which isincorporated by reference herein.

BACKGROUND ART

[0003] As recording media for recording various types of software suchas video data, audio data, or data for computers, recording media suchas magnetic disks, optical discs and magneto-optical discs have beenpopularized. For these recording media, various formats are prescribedby predetermined standards.

[0004] In recent years, the advancement of the high-efficiency codingtechnique has enabled band compression of all kinds of data includingvideo data so that these data are handled as digital data. Along withthis, increase in capacity of recording media and improvement inrecording density are demanded. As techniques for realizing a higherdensity of recording data, narrowing of the track pitch, change of thelinear velocity, change of the modulation system and the like may beconsidered.

[0005] However, in the case of increasing the recording capacity bychanging the recording density of an existing recording medium, theaddress management method on the disc differs depending on the recordingformat.

[0006] For example, with an existing magneto-optical disc, in the caseof recording data at a high density using a different recording format,the quantity of recording data increases and therefore a problem arisesthat clusters/sectors represented by ADIP (address in pre-groove)addresses recorded in advance on grooves of the magneto-optical disc donot coincide with data blocks, which are actually handled asrecording/reproducing units.

[0007] Random access is carried out with reference to ADIP address. Whenreading out data in random access, it is possible to read out desiredrecorded data by accessing a part near the position where the desireddata is recorded. However, when writing data, it is necessary to accessan accurate position in order not to overwrite and erase alreadyrecorded data. Therefore, it is important to accurately grasp the accessposition from the cluster/sector of each data block unit associated withADIP address.

DISCLOSURE OF THE INVENTION

[0008] It is an object of the present invention to provide a discrecording/reproducing device and a disc recording reproducing methodthat enable handling of the data volume with a higher density withoutcausing any inconvenience while utilizing the existing recordingformats, in the case of recording data onto a recording medium usingplural recording formats.

[0009] A disc recording/reproducing device according to the presentinvention is adapted for, with respect to a disc on which a unit clusterhaving a predetermined number 2N (where N is a positive integer) ofsectors as a set is formed and on which a sector address correspondingto each sector and a cluster address corresponding each cluster aremodulated in a predetermined manner and recorded in advance, performingrecording and reproduction using N sectors as a unit, which is obtainedby bisecting the unit cluster. The disc recording/reproducing deviceincludes: reproduction means for reproducing the cluster address and thesector address modulated in the predetermined manner and recorded inadvance, from the disc; identifier generation means for generating anidentifier that identifies the former N sectors or the latter N sectorsobtained by bisecting the cluster unit, as a recording unit used forrecording data; recording means for blocking inputted data into pluralblocks and recording the blocked data within the N-sector recordingunit; address generation means for generating an address correspondingto the plural blocks each that are formed in the N-sector recordingunit; and conversion means for converting the cluster address and thesector address reproduced by the reproducing means to an address unitincluding the identifier generated by the identifier generation means,the address generated by the address generation means and a recordingblock address generated on the basis of the cluster address; the addressunit obtained by conversion by the conversion means being recorded forthe plural blocks each, by the recording means.

[0010] This disc recording/reproducing device further includesgeneration means for generating an identifier that identifies arecording area when the disc has plural recording areas, and theidentifier generated by the generation means is added to the addressunit by the conversion means and thus recorded. Moreover, in this discrecording/reproducing device, the identifier generated by the generationmeans has a fixed value when the disc has a single recording area.

[0011] Another disc recording/reproducing device according to thepresent invention is adapted for, with respect to a disc on which a unitcluster having a predetermined number 2N (where N is a positive integer)of sectors added to a linking sector longer than an interleave length asa set is formed and on which a sector address corresponding to eachsector and a cluster address corresponding each cluster are modulated ina predetermined manner and recorded in advance, performing recording andreproduction using N sectors as a unit, which is obtained by bisectingthe unit cluster. The disc recording/reproducing device includes:reproduction means for reproducing the cluster address and the sectoraddress modulated in the predetermined manner and recorded in advance,from the disc; recording means for blocking inputted data into pluralblocks and recording the blocked data within the N-sector recordingunit; address generation means for generating an address correspondingto the plural blocks each that are formed in the N-sector recordingunit; and conversion means for converting the cluster address and thesector address reproduced by the reproducing means to an address unitincluding the address generated by the address generation means and arecording block address generated on the basis of the cluster address;the address unit obtained by conversion by the conversion means beingrecorded for the plural blocks each, by the recording means.

[0012] This disc recording/reproducing device further includesgeneration means for generating an identifier that identifies arecording area when the disc has plural recording areas, and theidentifier generated by the generation means is added to the addressunit by the conversion means and thus recorded. Moreover, in this discrecording/reproducing device, the identifier generated by the generationmeans has a fixed value when the disc has a single recording area.

[0013] A disc recording/reproducing method according to the presentinvention is adapted for, with respect to a disc on which a unit clusterhaving a predetermined number 2N (where N is a positive integer) ofsectors as a set is formed and on which a sector address correspondingto each sector and a cluster address corresponding each cluster aremodulated in a predetermined manner and recorded in advance, performingrecording and reproduction using N sectors as a unit, which is obtainedby bisecting the unit cluster. The disc recording/reproducing methodincludes: a step of reproducing the cluster address and the sectoraddress modulated in the predetermined manner and recorded in advance,from the disc; a step of generating an identifier that identifies theformer N sectors or the latter N sectors obtained by bisecting thecluster unit, as a recording unit used for recording data; a step ofgenerating an address corresponding to the plural blocks each that areformed in the N-sector recording unit; a step of converting thereproduced cluster address and sector address to an address unitincluding the generated identifier, the generated address and arecording block address generated on the basis of the cluster address;and a step of blocking inputted data into plural blocks, then recordingthe blocked data in the N-sector recording unit, and recording theaddress unit obtained by the conversion for the plural blocks each.

[0014] Another disc recording/reproducing method according to thepresent invention is adapted for, with respect to a disc on which a unitcluster having a predetermined number 2N (where N is a positive integer)of sectors added to a linking sector longer than an interleave length asa set is formed and on which a sector address corresponding to eachsector and a cluster address corresponding each cluster are modulated ina predetermined manner and recorded in advance, performing recording andreproduction using N sectors as a unit, which is obtained by bisectingthe unit cluster. The disc recording/reproducing method includes: a stepof reproducing the cluster address and the sector address modulated inthe predetermined manner and recorded in advance, from the disc; a stepof generating an address corresponding to the plural blocks each thatare formed in the N-sector recording unit; a step of converting thereproduced cluster address and sector address to an address unitincluding the generated address and a recording block address generatedon the basis of the cluster address; and a step of blocking inputteddata into plural blocks, then recording the blocked data within theN-sector recording unit, and recording the address unit obtained by theconversion for the plural blocks each.

[0015] The other objects of the present invention and specificadvantages provided by the present invention will be further clarifiedfrom the following description of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a view for explaining the specifications of anext-generation MD1 and a next-generation MD2 described as specificexamples of the present invention, and a conventional mini disc.

[0017]FIG. 2 is a view for explaining an RS-LDC block with BIS of anerror correcting system in the next-generation MD1 and thenext-generation MD2 described as specific examples of the presentinvention.

[0018]FIG. 3 is a view for explaining the BIS arrangement in onerecording block of the next-generation MD1 and the next-generation MD2described as specific examples of the present invention.

[0019]FIG. 4 is a schematic view for explaining the area structure onthe disc, surface of the next-generation MD1 described as a specificexample of the present invention.

[0020]FIG. 5 is a schematic view for explaining the area structure onthe disc surface of the next-generation MD2 described as a specificexample of the present invention.

[0021]FIG. 6 is a schematic view for explaining the area structure onthe disc surface in the case where audio data and PC data are recordedin a mixed manner on the next-generation MD1 described as a specificexample of the present invention.

[0022]FIG. 7 is a schematic view for explaining the data managementstructure of the next-generation MD1 described as a specific example ofthe present invention.

[0023]FIG. 8 is a schematic view for explaining the data managementstructure of the next-generation MD2 described as a specific example ofthe present invention.

[0024]FIG. 9 is a schematic view for explaining the relation between anADIP sector structure and a data block of the next-generation MD1 andthe next-generation MD2 described as specific example of the presentinvention.

[0025]FIG. 10A is a schematic view showing the ADIP data structure ofthe next-generation MD2. FIG. 10B is a schematic view showing the ADIPdata structure of the next-generation MD1.

[0026]FIG. 11 is a schematic view for explaining a modification of thedata management structure of the next-generation-MD2 described as aspecific example of the present invention.

[0027]FIG. 12 is a block diagram for explaining a disc drive device forperforming recording and reproduction compatible with thenext-generation MD1 and the next-generation MD2 described as specificexample of the present invention.

[0028]FIG. 13 is a block diagram for explaining a medium drive unit ofthe disc drive device.

[0029]FIG. 14 is a flowchart for explaining sector reproductionprocessing of the next-generation MD1 and the next-generation MD2 in thedisc drive device.

[0030]FIG. 15 is a flowchart for explaining sector recording processingof the next-generation MD1 and the next-generation MD2 in the disc drivedevice.

[0031]FIG. 16 is a view for explaining the relation between an ADIPaddress and an address unit of the next-generation MD1 described as aspecific example of the present invention.

[0032]FIG. 17 is a view for explaining the relation between an ADIPaddress and an address unit of the next-generation MD2 described as aspecific example of the present invention.

[0033]FIG. 18 is a view for explaining scrambling processing of alogical sector of the next-generation MD1 described as a specificexample of the present invention.

[0034]FIG. 19 is a view for explaining scrambling processing of alogical sector of the next-generation MD2 described as a specificexample of the present invention.

[0035]FIG. 20 is a circuit diagram for realizing address unit conversionaccording to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0036] Specific embodiments of the present invention will now bedescribed with reference to the drawings.

[0037] The present invention provides an address conversion method forperforming conversion from one address to another address between afirst address set for data and a second address set for a recordingformat on a recording medium. At least part of the second address iscaused to correspond to a part of the first address. A part lower thanleast significant position of the part of the first address is generatedin accordance with a predetermined rule, and a part higher than the mostsignificant position of the part of the first address is extended bypredetermined digit(s) so that the first address and the second addresscorrespond to each other. In the case of recording data in pluralrecording formats to the recording medium, it is practically possible tohandle a data volume with a higher density without causing anyinconvenience while utilizing the existing recording format.

[0038] In this disc drive device, a signal format that is different froman ordinary recording format used as a recording/reproducing format fora disc-like recording medium employing a conventional magneto-opticalrecording system is applied to this disc-like recording medium, thusrealizing increase in recording capacity of the conventionalmagneto-optical recording medium. Moreover, as a high-density recordingtechnique and a new file system are used, a recording format is providedthat enables significant increase in recording capacity whilemaintaining the compatibility of the appearance of casing and therecording/reproducing optical system with those of the conventionalmagneto-optical recording medium.

[0039] In this specific embodiment, as a disc-like magneto-opticalrecording medium, a recording medium of the mini disc (trademarkregistered) system is used. Particularly, a disc that has realizedincrease in recording capacity of the conventional magneto-opticalrecording medium by employing a format that is different from anordinarily used recording format will be explained as “next-generationMD1”, and a disc that has realized increase in recording capacity byapplying a new recording format to a new recording medium capable ofhigh-density recording will be explained as “next-generation MD2”.

[0040] Hereinafter, exemplary specifications of the next-generation MD1and the next-generation MD2 will be described, and processing togenerate recording data for both discs using an address conversionmethod according to the present invention will also be described.

[0041] 1. Disc Specifications and Area Structure

[0042] First, the specifications of the conventional mini disc, thenext-generation MD1 and the next-generation MD2 will be described withreference to FIG. 1. The physical format of the mini disc (and MD-DATA)is defined as follows. The track pitch is 1.6 μm. The bit length is 0.59μm/bit. The laser wavelength λ is λ=780 nm. The numerical aperture ofthe optical head is NA=0.45. As its recording system, a groove recordingsystem used for recording and reproduction based on grooves (on the discsurface) as tracks is employed. In an address system for this, asingle-spiral groove is formed on the disc surface, a meandering wobbleis formed on both sides of the groove at a predetermined frequency(22.05 kHz), and an absolute address is FM-modulated with reference tothe above-mentioned frequency and recorded to the wobbled groove track.In this specification, the absolute address recorded as a wobble is alsoreferred to as ADIP (address in pre-groove).

[0043] On the conventional MD, recording is performed using 32 sectorsas a main data part and 4 sectors as link sectors, that is, a total of36 sectors, as one cluster unit. The ADIP signal includes a clusteraddress and a sector address. The cluster address includes an 8-bitcluster H and an 8-bit cluster L. The sector address includes a 4-bitsector.

[0044] For the conventional mini disc, an EFM (8-14 modulation)modulation system is employed as a recording data modulation system. Asits error correcting system, ACIRC (advanced cross interleaveReed-Solomon code) is used. For data interleave, convolution isemployed. Therefore, the redundancy of data is 46.3%.

[0045] The data detecting system on the conventional mini disc is abit-by-bit system. As its disc driving system, a CLV (constant linearvelocity) system is used. The constant linear velocity is 1.2 m/s.

[0046] The standard data rate in recording and reproduction is 133 KB/s.The recording capacity is 164 MB (140 MB for MD-DATA). The minimumrewriting unit (unit cluster) of data includes 36 sectors, that is, 32main sectors and 4 link sectors, as described above.

[0047] Next, the next-generation MD1 described as the specificembodiment will be described. The next-generation MD1 has the samephysical specifications as the above-described conventional mini disc.Therefore, the track pitch is 1.6 μm. The laser wavelength λ is λ=780nm. The numerical aperture of the optical head is NA=0.45. As itsrecording system, the groove recording system is employed. As itsaddress system, ADIP is used. Since the structure of the optical systemin the disc drive device, the ADIP address reading system and the servoprocessing are the same as those for the conventional mini disc,compatibility with the conventional disc is achieved.

[0048] As the modulation system for recording data, the next-generationMD1 employs an RLL(1-7)PP modulation system (where RLL represents “runlength limited” and PP represents “parity preserve/prohibit rmtr(repeated minimum transition runlength)”). As its error correctingsystem, an RS-LDC (Reed Solomon-long distance code) system with BIS(burst indicator subcode) having higher correction capability is used.

[0049] Specifically, 2052 bytes, including 2048 bytes of user datasupplied from a host application or the like and an EDC (error detectioncode) of 4 bytes, are handled as 1 sector (that is, a data sectordifferent from a physical sector on the disc, which will be describedlater), and 32 sectors of sector 0 to sector 31 are grouped into a blockconsisting of 304 columns×216 rows, as shown in FIG. 2. Scramblingprocessing to take exclusive OR (EX-OR) with a predeterminedpseudo-random number is performed to 2052 bytes of each sector. To eachcolumn of the block to which scrambling processing has been thusperformed, a 32-byte parity is added to constitute an LDC (long distancecode) block of 304 columns×248 rows. Interleave processing is performedto this LDC block to form a block (interleaved LDC block) of 152columns×496 rows, and one column of the above-described BIS is arrangedevery 38 columns, thus forming a structure consisting of 155 columns×496rows, as shown in FIG. 3. Moreover, a frame synchronizing code (framesync) of 2.5 bytes is added to the leading end position, and each row iscaused to correspond to one frame, thus forming a structure consistingof 157.5 bytes×496 frames. The respective rows of FIG. 3 are equivalentto 496 frames of frame 10 to frame 505 of a data area in one recordingblock (cluster) shown in FIG. 9, which will be described later.

[0050] In the above-described data structure, data interleave is ofblock-completion type. This allows data redundancy of 20.50%. As thedata detecting system, a Viterbi decoding system based on PR(1, 2, 1)MLis used.

[0051] For the disc driving system, the CLV system is used with a linearvelocity is 2.4 m/s. The standard data rate in recording andreproduction is 4.4 MB/s. As this system is employed, a total recordingcapacity of 300 MB can be secured. Since the modulation system ischanged from the EFM modulation system to the RLL(1-7)PP modulationsystem, the window margin is increased from 0.5 to 0.666 and therefore ahigher density by 1.33 times can be realized. A cluster, which is theminimum data rewriting unit, includes 16 sectors, 64 KB. Since therecording modulation system is thus changed from the CIRC system to theRS-LDC system with BIS and the system using the difference in sectorstructure and Viterbi decoding, the data efficiency is improved from53.7% to 79.5% and therefore a higher density by 1.48 times can berealized.

[0052] By combining these, the next-generation MD1 can realize arecording capacity of 300 MB, which is approximately twice the recordingcapacity of the conventional mini disc.

[0053] On the other hand, the next-generation MD2 is a recording mediumto which a higher-density recording technique such as a domain walldisplacement detection system (DWDD) is applied. The next-generation MD2has a physical format that is different from those of theabove-described conventional mini disc and next-generation MD1. Thenext-generation MD2 has a track pitch of 1.25 μm and a bit length of0.16 μm/bit, and has a higher density in a linear direction.

[0054] To achieve compatibility with the conventional mini disc and thenext-generation MD1, the optical system, the reading system, the servoprocessing and the like are made conformable to the conventionalstandards, that is, laser wavelength λ=780 nm and numerical aperture ofthe optical head NA=0.45. The recording system is the groove recordingsystem. The address system is the system using ADIP. The casingappearance is also made conformable to the standards of the conventionalmini disc and the next-generation MD1.

[0055] However, when reading a narrow track pitch and linear density(bit length) than in the conventional technique as described above usingan optical system equivalent to that of the conventional mini disc orthe next-generation MD1, it is necessary to solve restraining conditionsin de-tracking margin, cross talk from lands and grooves, cross talk ofwobbles, focusing leakage, and CT signal. Therefore, the next-generationMD2 is characterized in that the depth, gradient, width and the like ofthe groove are changed. Specifically, the depth of the groove is definedwithin a range of 160 to 180 nm. The gradient is defined within a rangeof 60 to 70°. The width is defined within a range of 600 to 800 nm.

[0056] The next-generation MD2 employs the RLL(1-7)PP modulation system(where RLL represents “run length limited” and PP represents “paritypreserve/prohibit rmtr (repeated minimum transition runlength)”) adaptedfor high-density recording, as the modulation system for recording data.As the error correcting system, the RS-LDC (Reed Solomon-long distancecode) system with BIS having higher correction capability is used.

[0057] Data interleave is of block-completion type. This allows dataredundancy of 20.50%. The data detecting system is the Viterbi decodingsystem based on PR(1, −1)ML. A cluster, which is the minimum datarewriting unit, includes 16 sectors, 64 KB.

[0058] As the disc driving system, a ZCAV (zone constant angularvelocity) system is used with a linear velocity of 2.0 m/s. The standarddata rate in recording and reproduction is 9.8 MB/s. Therefore, thenext-generation MD2 can achieve a total recording capacity of 1 GB byemploying the DWDD system and this driving system.

[0059]FIGS. 4 and 5 show an exemplary area structure on the disc surfaceof the next-generation MD1 of this specific embodiment. Thenext-generation MD1 is the same medium as the conventional mini disc. Onthe innermost circular side of the disc, PTOC (premastered table ofcontents) is provided as a premastered area. In this area, discmanagement information is recorded as embossed pits based on physicalstructural deformation.

[0060] On the circular side outer than the premastered area, arecordable area is provided in which magneto-optical recording can bemade. This is a recordable/reproducible area in which a groove as aguide groove to a recording track is formed. On the innermost circularside of this recordable area, a UTOC (user table of contents) area isprovided. In this UTOC area, UTOC information is described, and a bufferarea with respect to the premastered area and a power calibration areaused for output power adjustment of a laser beam or the like areprovided.

[0061] The next-generation MD2 uses no pre-pits to realize a higherdensity, as shown in FIG. 5. Therefore, the next-generation MD2 has noPTOC area. On the next-generation MD2, a unique ID (UID) area to recordinformation for copyright protection, information for checking datafalsification, other non-public information and the like is provided inan area inner than the recordable area. In this UID area, information isrecorded in a recording format that is different from the DWDD systemapplied to the next-generation MD2.

[0062] On the next-generation MD1 and the next-generation MD2, audiotracks for music data and data tracks can be recorded in a mixed manner.In this case, an audio recording area AA in which at least one audiotrack is recorded and a PC data recording area DA in which at least onedata track is recorded are formed at arbitrary positions in the dataarea, for example, as shown in FIG. 6.

[0063] A series of audio track and data track need not necessarilyrecorded in a physically continuous manner on the disc but may bedividedly recorded as plural parts as shown in FIG. 6. Parts meanssections that are recorded in a physically continuous manner.Specifically, even when there are two PC data recording areas that arephysically separate as shown in FIG. 6, the number of data tracks may beone or plural. While FIG. 6 shows the physical specifications of thenext-generation MD1, the audio recording area AA and the PC datarecording area DA can be similarly recorded on the next-generation MD2in a mixed manner.

[0064] A specific example of a recording/reproducing device compatiblewith the next-generation MD1 and the next-generation MD2 having theabove-described physical specifications will be later described indetail.

[0065] 2. Management Structure of Disc

[0066] The management structure of the disc of this specific embodimentwill be described with reference to FIGS. 7 and 8. FIG. 7 shows the datamanagement structure of the next-generation MD1. FIG. 8 shows the datamanagement structure of the next-generation MD2.

[0067] Since the next-generation MD1 is the same medium as theconventional mini disc as described above, PTOC is recorded on thenext-generation MD1 in the form of embossed pits that cannot berewritten, as employed in the conventional mini disc. In this PTOC, thetotal capacity of the disc, the UTOC position in the UTOC area, theposition of the power calibration area, the start position of the dataarea, the end position of the data area (lead-out position) and the likeare recorded as management information.

[0068] On the next-generation MD1, the power calibration area (rec powercalibration area) for adjusting the writing output of a laser isprovided at ADIP addresses 0000 to 0002. At the subsequent addresses0003 to 0005, UTOC is recorded. UTOC includes management informationthat is rewritten in accordance with recording, erasure and the like oftracks (audio track/data track) and manages the start position, the endposition and the like of the respective tracks and parts constitutingthe tracks. UTOC also manages parts in a free area in which no track hasbeen recorded yet, that is, a writable area. In UTOC, the whole PC datais managed as one track independent of MD audio data. Therefore, even ifan audio track and a data track are recorded in a mixed manner, therecording positions of PC data divided into plural parts can be managed.

[0069] UTOC data is recorded in a specified ADIP cluster in this UTOCarea. The content of the UTOC data is defined by each sector in thisADIP cluster. Specifically, UTOC sector 0 (the leading ADIP sector inthis ADIP cluster) manages parts corresponding to the tracks and freearea. UTOC sector 1 and UTOC sector 4 manages character informationcorresponding to the tracks. In UTOC sector 2, information for managingthe recording date and time corresponding to the tracks is written.

[0070] UTOC sector 0 is a data area in which recorded data, recordablenon-recorded area, data management information and the like arerecorded. For example, when recording data to the disc, the disc drivedevice finds out a non-recorded area on the disc from the UTOC sector 0and records data into this area. In reproduction, the disc drive devicejudges, from UTOC sector 0, the area where a data track to be reproducedis recorded, and accesses that area to perform reproduction.

[0071] On the next-generation MD1, PTOC and UTOC are recorded as datamodulated in accordance with a system conformable to the conventionalmini disc system, that is, in this case, the EFM modulation system.Therefore, the next-generation MD1 has an area where data modulated inaccordance with the EFM modulation system is recorded, and an area wherehigh-density data modulated in accordance with the RS-LDC and RLL(1-7)PPmodulation systems is recorded.

[0072] An alert track described at ADIP address 0032 stores informationfor notification to the effect that the next-generation MD1 is notsupported by a disc driver device for the conventional mini disc evenwhen the next-generation MD1 is inserted into the disc driver device forthe conventional mini disc. This information may be audio data that says“The format of this disc is not supported by this reproducing device,”or warning sound data. In the case of a disc driver device having adisplay unit, this information may be data for displaying thenotification. This alert track is recorded in accordance with the EFMmodulation system so that it can be read by the disc driver devicecorresponding to the conventional mini disc.

[0073] At ADIP address 0034, a disc description table (DDT) describingdisc information of the next-generation MD1 is recorded. In DDT, theformat, the total number of logical clusters on the disc, proper ID ofthe medium, update information of this DDT, defective clusterinformation and the like are described.

[0074] In the DDT area and subsequent areas, data is recorded ashigh-density data modulated in accordance with the RS-LDC and RLL(1-7)PPmodulation systems. Therefore, a guard band area is provided between thealert track and DDT.

[0075] At the earliest ADIP address where high-density data modulated bythe RLL(1-7)PP modulation system is recorded, that is, at the leadingaddress of DDT, a logical cluster number (LCN) is appended, whichdefines this address as 0000. One logical cluster includes 65,536 bytes.This logical cluster is a minimum unit for reading/writing. ADIPaddresses 0006 to 0031 are reserved.

[0076] At the subsequent ADIP addresses 0036 to 0038, a secure area isprovided, which can be made public by authentication. This secure areamanages attributes representing whether the respective clustersconstituting data can be made public or not. Particularly, informationfor copyright protection, information for checking data falsificationand the like are recorded in this secure area. Various other non-publicinformation can be recorded, too. This non-public area allows limitedaccess by a specially permitted specific external device, and alsoincludes information for authenticating this external device that isallowed to access this area.

[0077] At ADIP address 0038 and the subsequent ADIP addresses, a userarea (with an arbitrary data length) where writing and reading can befreely carried out, and a spare area (with a data length 8) aredescribed. Data recorded in the user area, when arrayed in LCN ascendingorder, is sectioned into user sectors in which 2,048 bytes from theleading end form one unit. An external device such as PC manages thisdata by appending a user sector number (USN) of 0000 for the leadinguser sector and using an FAT file system.

[0078] The data management structure of the next-generation MD2 will nowbe described with reference to FIG. 8. The next-generation MD2 has noPTOC. Therefore, all the disc management information such as the totalcapacity of the disc, the position of the power calibration area, thestart position of the data area and the end position of the data area(lead-out position) is included as PDPT (pre-format disc parametertable) in ADIP information and thus recorded. Data is modulated inaccordance with the RS-LDC modulation system with BIS and the RLL(1-7)PPmodulation system and recorded in the DWDD format.

[0079] In a lead-in area and a lead-out area, the laser powercalibration area (PCA) is provided. On the next-generation MD2, LCN 0000is appended to an ADIP address following PCA.

[0080] On the next-generation MD2, a control area equivalent to the UTOCarea of the next-generation MD1 is prepared. FIG. 8 shows a unique ID(UID) area where information for copyright protection, information forchecking data falsification and other non-public information arerecorded. Actually, this UID area is provided at a position inner thanthe lead-in area, and data is recorded therein in a recording formatthat is different from the ordinary DWDD format.

[0081] Files of the next-generation MD1 and the next-generation MD2 aremanaged on the basis of FAT file systems. For example, the respectivedata tracks have individual FAT file systems. Alternatively, one FATfile system may be recorded to cover plural data tracks.

[0082] 3. ADIP Sector/Cluster Structure and Data Block

[0083] The relation between the ADIP sector structures and data blocksof the next-generation MD1 and the next-generation MD2 described in thespecific embodiment of the present invention will now be described withreference to FIG. 9. The conventional mini disc (MD) system employs acluster/sector structure corresponding to the physical address recordedas ADIP. In this embodiment, a cluster based on the ADIP address isreferred to as “ADIP cluster”, as a matter of convenience. A clusterbased on the address on the next-generation MD1 and the next-generationMD2 is referred to as “recording block” or “next-generation MD cluster”.

[0084] On the next-generation MD1 and the next-generation MD2, a datatrack is handled as a data stream recorded in the form of continuousclusters, which are minimum units of address, as shown in FIG. 9.

[0085] As shown in FIG. 9, in the case of the next-generation MD1, oneconventional cluster (36 sectors) is bisected so that one recordingblock consists of 18 sectors. In the case of the next-generation MD2,one recording block consists of 16 sectors.

[0086] The data structure of one recording block (one next-generation MDcluster) shown in FIG. 9 includes 512 frames, that is, a preamble madeup of 10 frames, a postamble made up of 6 frames, and a data part madeup of 496 frames. One frame in this recording block includes asynchronizing signal area, data, BIS and DSV.

[0087] Of the 512 frames of one recording block, each of groups offrames obtained by equally dividing 496 frames where main data isrecorded into 16 is referred to as address unit. Each address unitincludes 31 frames. The number of this address unit is referred to asaddress unit number (AUN). This AUN is a number appended to all addressunits and is used for address management of recording signals.

[0088] In the case of recording high-density data modulated inaccordance with the 1-7PP modulation system to the conventional minidisc having the physical cluster/sector structure described in ADIP asin the next-generation MD1, a problem arises that the ADIP addressoriginally recorded on the disc and the address of the actually recordeddata block do not coincide with each other. In random access, which iscarried out with reference to the ADIP address, even if a position nearthe position where desired data is recorded is accessed when reading outdata, the recorded data can be read out. However, when writing data, itis necessary to access an accurate position so as not to overwrite anderase already recorded data. Therefore, it is important to accuratelygrasp the access position from the next-generation MDcluster/next-generation MD sector corresponding to the ADIP address.

[0089] Thus, in the case of the next-generation MD1, the high-densitydata cluster is grasped, using a data unit obtained by converting theADIP address recorded as a wobble on the medium surface in accordancewith a predetermined rule. In this case, an integral multiple of theADIP sector is caused to be the high-density data cluster. On the basisof this idea, when describing the next-generation MD cluster withrespect to one ADIP cluster recorded on the conventional mini disc, eachnext-generation MD cluster is caused to correspond to a ½-ADIP cluster(18 sectors).

[0090] Therefore, in the case of the next-generation MD1, a ½-cluster ofthe conventional MD cluster is handled as a minimum recording unit(recording block).

[0091] On the other hand, in the case of the next-generation MD2, onecluster is handled as one recording block.

[0092] In this specific embodiment, a data block made up of 2048 bytesas a unit supplied from the host application is handled as one logicaldata sector (LDS), and a set of 32 logical data sectors recorded in thesame recording block is handled as a logical data cluster (LDC), asdescribed above.

[0093] With the data structure as described above, when recordingnext-generation MD data to an arbitrary position, recording to themedium at good timing can be realized. Moreover, as an integral numberof next-generation MD clusters are included in an ADIP cluster, which isan ADIP address unit, the address conversion rule for converting theADIP cluster address to the next-generation MD data cluster address issimplified and the circuit or software structure for the conversion canbe simplified.

[0094] While two next-generation MD clusters are caused to correspond toone ADIP cluster in the example shown in FIG. 9, three or morenext-generation MD clusters can be arranged with respect to one ADIPcluster. In this case, one next-generation MD cluster is not limited tothe construction made up of 16 ADIP sectors. The next-generation MDcluster can be set in accordance with the difference in data recordingdensity between the EFM modulation system and the RLL(1-7)PP modulationsystem, the number of sectors constituting a next-generation cluster,the size of one sector and the like.

[0095] While FIG. 9 shows the data structure on the recording medium, adata structure in the case where an ADIP signal recorded on a groovewobble track on the recording medium is demodulated by an ADIPdemodulator 38 of FIG. 13, which will be described later, will now beexplained.

[0096]FIG. 10A shows the data structure of ADIP of the next-generationMD2. FIG. 10B shows the data structure of ADIP of the next-generationMD1.

[0097] In the case of the next-generation MD1, a synchronizing signal,cluster H information and cluster L information representing clusternumbers on the disc, sector information including sector numbers in thecluster are described. The synchronizing signal is described by 4 bits.The cluster H is described by upper 8 bits of address information. Thecluster L is described by lower 8 bits of the address information. Thesector information is described by 8 bits. CRC is added to the latter 14bits. In this manner, an ADIP signal of 42 bits is recorded in each ADIPsector.

[0098] In the case of the next-generation MD2, synchronizing signal dataof 4 bits, cluster H information of 4 bits, cluster M information of 8bits, cluster L information of 4 bits, and sector information of 4 bitsare described. A BCH parity is added to the latter 18 bits. Also in thecase of the next-generation MD2, an ADIP signal of 42 bits is similarlyrecorded in each ADIP sector.

[0099] In the data structure of ADIP, the construction of theabove-described cluster H information, cluster M information and clusterL information can be arbitrarily decided. Alternatively, otheradditional information can be described in this part. For example, in anADIP signal on the next-generation MD2, cluster information isrepresented by a cluster H of upper 8 bits and a cluster L of lower 8bits, as shown in FIG. 11, and disc control information can be describedinstead of the cluster L of lower 8 bits. The disc control informationmay be a servo signal correction value, upper limit value of reproducinglaser power, linear velocity correction coefficient for reproducinglaser power, upper limit value of recording laser power, linear velocitycorrection coefficient for recording laser power, recording magneticsensitivity, magnetism-laser pulse phase difference, parity and thelike.

[0100] 4. Disc Drive Device

[0101] A specific example of a disc drive device 10 capable ofperforming recording and reproduction of the next-generation MD1 and thenext-generation MD2 will be described with reference to FIGS. 12 and 13.The disc drive device 10 can be connected to a personal computer(hereinafter referred to as PC) 100 and can use the next-generation MD1and the next-generation MD2 as external storage for audio data and forPC and the like.

[0102] The disc drive device 10 has a medium drive unit 11, a memorytransfer controller 12, a cluster buffer memory 13, an auxiliary memory14, USB interfaces 15, 16, a USB hub 17, a system controller 18, and anaudio processing unit 19.

[0103] The medium drive unit 11 performs recording to/reproduction froman individual disc 90 loaded thereon such as the conventional mini disc,the next-generation MD1 or the next-generation MD2. The internalstructure of the medium drive unit 11 will be described later withreference to FIG. 13.

[0104] The memory transfer controller 12 controls transmission/receptionof reproduction data from the medium drive unit 11 and recording data tobe supplied to the medium drive unit 11. The cluster buffer memory 13buffers data read out by each high-density data cluster from a datatrack of the disc 90 by the medium drive unit 11, under the control ofthe memory transfer controller 12. The auxiliary memory 14 storesvarious management information and special information such as UTOCdata, CAT data, unique ID and hash value read out from the disc by themedium drive unit 11, under the control of the memory transfercontroller 12.

[0105] The system controller 18 can communicate with the PC 100connected via the USB interface 16 and the USB hub 17. The systemcontroller 18 controls communication with the PC 100, performs receptionof commands such as a writing request and a reading request andtransmission of status information and other necessary information, andintegrally controls the whole disc drive device 10.

[0106] For example, when the disc 90 is loaded on the medium drive unit11, the system controller 18 instructs the medium drive unit 11 to readout management information and the like from the disc 90 and causes thememory transfer controller 12 to control the auxiliary memory 14 tostore the read-out management information and the like such as PTOC andUTOC.

[0107] By reading the management information, the system controller 18can grasp the track recording state of the disc 90. Moreover, by readingCAT, the system controller 18 can grasp the high-density data clusterstructure within the data track and can be ready to respond to an accessrequest for the data track from the PC 100.

[0108] With the unique ID and the hash value, the system controller 18executes disc authentication processing and other processing, transmitsthese values to the PC 100, and causes the disc authenticationprocessing and other processing to be executed on the PC 100.

[0109] When a reading request for a certain FAT sector is sent from thePC 100, the system controller 18 gives the medium drive unit 11 a signalfor reading out a high-density data cluster containing this FAT sector.The read-out high-density data cluster is written to the cluster buffermemory 13 by the memory transfer controller 12. However, if the data ofthe FAT sector has already been stored in the cluster buffer memory 13,the medium drive unit 11 need not read out the data.

[0110] In this case, the system controller 18 performs control to give asignal for reading out the data of the requested FAT sector from thedata of the high-density data cluster that is being written to thecluster buffer memory 13, and to send the signal to the PC 100 via theUSB interface 15 and the USB hub 17.

[0111] When a writing request for a certain FAT sector is sent from thePC 100, the system controller 18 causes the medium drive unit 11 to readout a high-density data cluster containing this FAT sector. The read-outhigh-density data cluster is written to the cluster buffer memory 13 bythe memory transfer controller 12. However, if the data of the FATsector has already been stored in the cluster buffer memory 13, themedium drive unit 11 need not read out the data.

[0112] The system controller 18 also supplies data of a FAT sector(recording data) sent from the PC 100, to the memory transfer controller12 via the USB interface 15, and causes the memory transfer controller12 to rewrite the data of the corresponding FAT sector on the clusterbuffer memory 13.

[0113] The system controller 18 also instructs the memory transfercontroller 12 to transfer to the medium drive unit 11 the data of thehigh-density data cluster stored in the cluster buffer memory 13 inwhich the requested FAT sector has been rewritten, as recording data. Inthis case, the medium drive unit 11 modulates and writes the recordingdata of the high-density data cluster, in accordance with the EFMmodulation system if the loaded medium is the conventional mini disc, orin accordance with the RLL(1-7)PP modulation system if the loaded mediumis the next-generation MD1 or the next-generation MD2.

[0114] In the disc drive device 10 described in this embodiment, theabove-described recording/reproduction control is the control in thecase of recording/reproducing a data track. Data transfer inrecording/reproducing an MD audio data (audio track) is performed viathe audio processing unit 19.

[0115] The audio processing unit 19 has, for example, an analog audiosignal input part such as a line input circuit/microphone input circuit,an A/D converter, and a digital audio data input part, as an inputsystem. The audio processing unit 19 also has an ATRAC compressionencoder/decoder and a buffer memory for compressed data. The audioprocessing unit 19 also has a digital audio data output part, a D/Aconverter, and an analog audio signal output part such as a line outputcircuit/headphone output circuit, as an output system.

[0116] An audio track is recorded onto the disc 90 when digital audiodata (or analog audio signal) is inputted to the audio processing unit19. The inputted linear PCM digital audio data, or linear PCM audio dataobtained by converting the inputted analog audio signal at the A/Dconverter, is ATRAC compression-encoded and stored into the buffermemory. After that, the audio data is read out from the buffer memory atpredetermined timing and transferred to the medium drive unit 11.

[0117] The medium drive unit 11 modulates the transferred compresseddata in accordance with the EFM modulation system or the RLL(1-7)PPmodulation system and writes the modulated data to the disc 90 as anaudio track.

[0118] When reproducing an audio track from the disc 90, the mediumdrive unit 11 demodulates reproduced data to ATRAC compressed data andtransfers the demodulated data to the audio processing unit 19. Theaudio processing unit 19 performs ATRAC compression decoding to obtainlinear PCM audio data and outputs the linear PCM audio data from thedigital audio data output part.

[0119] This structure shown in FIG. 12 is simply an example. The audioprocessing unit 19 is not necessary, for example, when the disc drivedevice 10 is connected with the PC 100 and is used as an externalstorage device for recording and reproducing only a data track. On theother hand, when the main purpose is to record and reproduce audiosignals, it is preferred that the audio processing unit 19 is providedand that an operating unit and a display unit as user interfaces areprovided. For the connection with the PC 100, not only USB but also aso-called IEEE1394 interface conformable to the standards prescribed byIEEE (Institute of Electrical and Electronics Engineers) andgeneral-purpose connection interfaces can be applied.

[0120] Next, the structure of the medium drive unit 11 for recording andreproduction of the conventional mini disc, the next-generation MD1 andthe next-generation MD2 will be described further in detail withreference to FIG. 13.

[0121] The medium drive unit 11 is characterized in that in order torecord data to and reproduce data from the conventional mini disc, thenext-generation MD1 and the next-generation MD2, it has a structure forexecuting EFM modulation and ACIRC encoding for recording on theconventional mini disc and a structure for executing RLL(1-7)PPmodulation and RS-LDC encoding for recording on the next-generation MD1and the next-generation MD2, particularly as a recording processingsystem. The medium drive unit 11 is also characterized in that it has astructure for executing EFM demodulation and ACIRC decoding forreproduction from the conventional mini disc and a structure forexecuting RLL(1-7) demodulation based on data detection using PR(1, 2,1)ML and Viterbi decoding, and RS-LDC decoding for reproduction from thenext-generation MD1 and the next-generation MD2, as a reproductionprocessing system.

[0122] The medium drive unit 11 rotationally drives the loaded disc 90in the CLV system or the ZCAV system, using a spindle motor 21. Inrecording and reproduction, a laser beam is cast on the disc 90 from anoptical head 22.

[0123] In recording, the optical head 22 outputs a laser beam of a highlevel for heating the recording track to the Curie temperature. Inreproduction, the optical head 22 outputs a laser beam of a relativelylow level for detecting data from reflected light by a magnetic Kerreffect. Therefore, the optical head 22 is equipped with an opticalsystem including a laser diode as a laser output unit, a polarizing beamsplitter, an objective lens and like, and a detector for detectingreflected light. The objective lens provided in the optical head 22 isheld in such a manner that it can be displaced in a disc radialdirection and a direction toward/away from the disc, for example, by abiaxial mechanism.

[0124] In this specific embodiment, in order to realize a maximumreproducing characteristic for the conventional mini disc, thenext-generation MD1 and the next-generation MD2, which differ inphysical specifications of medium surface, a phase compensating platethat can optimize the bit error rate at the time of data reading for allthe discs is provided in the optical path of reading light of theoptical head 22.

[0125] A magnetic head 23 is arranged at a position opposite to theoptical head 22 with respect to the disc 90. The magnetic head 23applies a magnetic field modulated by recording data, to the disc 90.Although not shown, a thread motor and a thread mechanism for moving thewhole optical head 22 and the magnetic head 23 in the disc radialdirection are provided.

[0126] In this medium drive unit 11, a recording processing system, areproduction processing system, a servo system and the like areprovided, in addition to a recording/reproducing head system includingthe optical head 22 and the magnetic head 23, and a disc rotationaldriving system including the spindle motor 21. As the recordingprocessing system, a part for performing EFM modulation and ACIRCencoding at the time of recording to the conventional mini disc, and apart for performing RLL(1-7)PP modulation and RS-LDC encoding at thetime of recording to the next-generation MD1 and the next-generation MD2are provided.

[0127] As the reproduction processing system, a part for performingdemodulation corresponding to EFM modulation and ACIRC decoding at thetime of reproduction from the conventional mini disc, and a part forperforming demodulation corresponding to RLL(1-7)PP modulation (i.e.,RLL(1-7) demodulation based on data detection using PR(1, 2, 1)ML andViterbi decoding) and RS-LDC decoding at the time of reproduction formthe next-generation MD1 and the next-generation MD2 are provided.

[0128] Information detected as reflected light of a laser beam cast onthe disc 90 from the optical head 22 (i.e., photocurrent obtained as thephotodetector detects the reflected light of the laser beam) is suppliedto an RF amplifier 24. The RF amplifier 24 performs current-voltageconversion, amplification, matrix calculation and the like to theinputted detected information and extracts a reproduction RF signal, atracking error signal TE, a focusing error signal FE, groove information(ADIP information recorded by wobbling of the track on the disc 90) andthe like as reproduction information.

[0129] In reproduction from the conventional mini disc, the reproductionRF signal obtained at the RF amplifier is passed through a comparator 25and a PLL circuit 26 and processed by an EFM demodulator 27 and an ACIRCdecoder 28. The reproduction RF signal is binarized into an EFM signalstring and then EFM-demodulated by the EFM demodulator 27. Moreover,error correction and de-interleave processing are performed to theresulting signal by the ACIRC decoder 28. In the case of audio data,ATRAC compressed data is obtained at this point. In this case, aselector 29 selects a conventional mini disc signal side and thedemodulated ATRAC compressed data is outputted to a data buffer 30 asreproduction data from the disc 90. In this case, the compressed data issupplied to the audio processing unit 19 of FIG. 12.

[0130] On the other hand, in reproduction from the next-generation MD1or the next-generation MD2, the reproduction RF signal obtained at theRF amplifier is passed through an A/D converter circuit 31, an equalizer32, a PLL circuit 33 and a PRML circuit 34 and processed by anRLL(1-7)PP demodulator 35 and an RS-LDC decoder 36. At the RLL(1-7)PPdemodulator 35, reproduction data as an RLL(1-7) code string is obtainedfrom the reproduction RF signal on the basis of data detection usingPR(1, 2, 1) ML and Viterbi decoding, and RLL(1-7) demodulationprocessing is performed to this RLL(1-7) code string. Moreover, errorcorrection and de-interleave processing are performed by the RS-LDCdecoder 36.

[0131] In this case, the selector 29 selects a next-generationMD1/next-generation MD2 side and the demodulated data is outputted tothe data buffer 30 as reproduction data from the disc 90. In this case,the demodulated data is supplied to the memory transfer controller 12 ofFIG. 12.

[0132] The tracking error signal TE and the focusing error signal FEoutputted from the RF amplifier 24 are supplied to the servo circuit 37.The groove information is supplied to the ADIP demodulator 38.

[0133] The ADIP demodulator 38 limits the band of the groove informationusing a band-pass filter so as to extract a wobble component and thenperforms FM demodulation and biphasic demodulation to extract an ADIPaddress. In the case of the conventional mini disc or thenext-generation MD1, the extracted ADIP address, which is absoluteaddress information on the disc, is supplied to a drive controller 41via an MD address demodulator 39. In the case of the next-generationMD2, the ADIP address is supplied to the drive controller 41 via anext-generation MD2 address decoder 40.

[0134] The drive controller 41 executes predetermined control processingbased on each ADIP address. The groove information is sent back to theservo circuit 37 for spindle servo control.

[0135] The servo circuit 37 generates a spindle error signal for CLVservo control and ZCAV servo control, on the basis of an error signalobtained by integrating a phase difference between the grooveinformation and a reproducing clock (PLL clock at the time of decoding).

[0136] The servo circuit 37 also generates various servo control signals(tracking control signal, focusing control signal, thread controlsignal, spindle control signal and the like), based on the spindle errorsignal, the tracking error signal and the focusing error signal suppliedfrom the RF amplifier 24 as described above, and a track jump command,an access command and the like from the drive controller 41. The servocircuit 37 outputs these servo control signals to a motor driver 42.That is, the servo circuit 37 performs necessary processing such asphase compensation processing, gain processing and target value settingprocessing in response to the servo error signal and commands, and thusgenerates the various servo control signals.

[0137] The motor driver 42 generates predetermined servo drive signalsbased on the servo control signals supplied from the servo circuit 37.The servo drive signals of this case include a biaxial drive signal(focusing direction and tracking direction) for driving the biaxialmechanism, a thread motor driving signal for driving the threadmechanism, and a spindle motor driving signal for driving the spindlemotor 21. In response to such servo drive signals, focusing control andtracking control on the disc 90 and CLV control or ZCAV control on thespindle motor 21 are performed.

[0138] When the recording operation to the disc 90 is performed,high-density data from the memory transfer controller 12 shown in FIG.12 or normal ATRAC compressed data from the audio processing unit 19 issupplied.

[0139] In recording to the conventional mini disc, a selector 43 isconnected to a conventional mini disc side, and an ACIRC encoder and anEFM modulator 45 function. In the case of an audio signal, compresseddata from the audio processing unit 19 is interleaved and given an errorcorrection code by the ACIRC encoder 44 and then EFM-modulated by theEFM modulator 45. The EFM-modulated data is supplied to a magnetic headdriver 46 via the selector 43 and the magnetic head 23 applies amagnetic field based on the EFM-Modulated data to the disc 90, therebyrecording the modulated data.

[0140] In recording to the next-generation MD1 and the next-generationMD2, the selector 43 is connected to a next-generationMD1/next-generation MD2 side, and an RS-LDC encoder 47 and an RLL(1-7)PPmodulator 48 function. In this case, high-density data sent from thememory transfer controller 12 is interleaved and given an errorcorrection code of the RS-LDC system by the RS-LDC encoder 47 and thenRLL(1-7)-modulated by the RLL(1-7)PP modulator 48.

[0141] The recording data modulated to the RLL(1-7) code string issupplied to the magnetic head driver 46 via the selector 43 and themagnetic head 23 applies a magnetic field based on the modulated data tothe disc 90, thereby recording the data.

[0142] A laser driver/APC 49 causes the laser diode to execute a laserbeam emitting operation in the reproduction and recording as describedabove. It also performs a so-called APC (automatic laser power control)operation. Specifically, a detector for monitoring the laser power isprovided in the optical head 22, though not shown, and its monitorsignal is fed back to the laser driver/APC 49. The laser driver/APC 49compares the current laser power acquired as the monitor signal withpredetermined laser power and reflects the difference between them ontoa laser driving signal, thereby controlling the laser power outputtedfrom the laser diode so that the laser power is stabilized at a presetvalue. Values of reproducing laser power and recording laser power areset in a register within the laser driver/APC 49 by the drive controller41.

[0143] On the basis of instructions from the system controller 18, thedrive controller 41 controls each structural unit so that theabove-described operations (operations of access, various servo, datawriting and data reading) are executed. The parts surrounded bychain-dotted lines in FIG. 13 can be constituted as a one-chip circuit.

[0144] In the case a data track recording area and an audio trackrecording area are dividedly set on the disc 90 as shown in FIG. 6, thesystem controller 18 instructs the drive controller 41 of the mediumdrive unit 11 to access a preset recording area in accordance withwhether data to be recorded or reproduced is on an audio track or a datatrack.

[0145] It is also possible to perform control so that recording of onlyone of PC data and audio data to the loaded disc 90 is permitted whilerecording of the other data is prohibited. That is, it is possible toperform control so that PC data and audio data do not exist in a mixedmanner.

[0146] Thus, the disc drive device 10 described in this embodiment hasthe above-described structure and therefore can realize compatibilitybetween the conventional mini disc, the next-generation MD1 and thenext-generation MD2.

[0147] 5. Sector Reproduction Processing on Data Track

[0148] Reproduction processing and recording processing to thenext-generation MD1 and the next-generation MD2 by the above-describeddisc drive device 10 will now be described. In access to a data area, aninstruction to record or reproduce data by each “logical sector(hereinafter referred to as FAT sector)” is given, for example, from theexternal PC 100 to the system controller 18 of the disc drive device 10via the USB interface 16. A data cluster, as viewed from the PC 100, issectioned every 2048 bytes and managed on the basis of the FAT filesystem in USN ascending order, as shown in FIG. 7. On the other hand,the minimum rewriting unit of a data track on the disc 90 is anext-generation MD cluster having a size of 65,536 bytes, and thisnext-generation MD cluster is provided with LCN.

[0149] The size of a data sector referred to by FAT is smaller than thatof a next-generation MD cluster. Therefore, in the disc drive device 10,a user sector referred to by FAT must be converted to a physical ADIPaddress and reading/writing of data by each data sector referred to byFAT must be converted to reading/writing of data by each next-generationMD cluster, using the cluster buffer memory 13.

[0150]FIG. 14 shows the processing in the system controller 18 of thedisc drive device 10 in the case a reading request for a certain FATsector is sent from the PC 100.

[0151] When the system controller 18 receives a reading command for FATsector #n from the PC 100 via the USB interface 16, the systemcontroller 18 performs processing to find the next-generation MD clusternumber of the next-generation MD cluster containing the FAT sector ofthe designated FAT sector number #n.

[0152] First, provisional next-generation MD cluster number u0 isdecided. The size of a next-generation MD cluster is 65,536 bytes andthe size of a FAT sector is 2048 bytes. Therefore, 32 FAT sectors existin one next-generation MD cluster. FAT sector number (n) divided by 32with the remainder rounded down, that is, u0, becomes the provisionalnext-generation MD cluster number.

[0153] Then, with reference to the disc information read into theauxiliary memory 14 from the disc 90, the number of next-generation MDclusters ux other than the clusters for data recording is found. Thatis, the number of next-generation MD clusters in the secure area isfound.

[0154] As described above, some of the next-generation MD clusters inthe data track are not made public as a data recordable/reproduciblearea. Therefore, the number of non-public clusters ux is found on thebasis of the disc information read into the auxiliary memory 14 inadvance. After that, the number of non-public clusters ux is added tonext-generation MD cluster number u0, and the result of addition u isused as actual next-generation MD cluster number #u.

[0155] As next-generation MD cluster number #u of the next-generation MDcluster containing FAT sector number #n is found, the system controller18 judges whether or not the next-generation MD cluster of clusternumber #u has already been read out from the disc 90 and stored in thecluster buffer memory 13. If not, the system controller 18 reads it fromthe disc 90.

[0156] The system controller 18 finds ADIP address #a from the read-outnext-generation MD cluster number #u and thus reading out thenext-generation MD cluster from the disc 90.

[0157] The next-generation MD cluster might be dividedly recorded inplural part on the disc 90. Therefore, to find the ADIP address where itis recorded, these parts must be sequentially searched. Thus, from thedisc information read out into the auxiliary memory 14, the number ofnext-generation MD clusters p recorded in the leading part of the datatrack and the leading next-generation MD cluster number px are found.

[0158] Since the start address/end address is recorded in the form ofADIP address in each part, the number of next-generation MD clusters pand the leading next-generation MD cluster number px can be found fromthe ADIP cluster address and the part length. Next, it is judged whetherthis part includes the next-generation MD cluster of the target clusternumber #u or not. If not, the next part is searched. That is, the partindicated by link information of the previously considered part issearched. In this manner, the parts described in the disc informationare sequentially searched and the part containing the targetnext-generation MD cluster is discriminated.

[0159] When the part in which the target next-generation MD cluster (#u)is recorded is found, the difference between next-generation MD clusternumber px recorded at the leading end of this part and the targetnext-generation MD cluster number #u is found and an offset from theleading end of the part to the target next-generation MD cluster (#u) isthus acquired.

[0160] In this case, since two next-generation MD clusters are writtenin one ADIP cluster, this offset may be divided by 2 and thus convertedto an ADIP address offset f (where f (u−px)/2).

[0161] However, if a fraction of 0.5 is generated, writing starts at acentral part of the cluster f. Finally, the offset f is added to thecluster address part at the leading ADIP address of this part, that is,at the start address of the part, and ADIP address #a of the recordingdestination to which the next-generation MD cluster (#u) is to beactually written can be thus found. The processing up to this point isequivalent to the processing to set the reproduction start address andthe cluster length at step S1. In this case, it is assumed thatdiscrimination of the conventional mini disc, the next-generation MD1 orthe next-generation MD2 has already been completed.

[0162] As ADIP address #a is found, the system controller 18 instructsthe medium drive unit 11 to access ADIP address #a. Therefore, themedium drive unit 11 executes access to ADIP address #a under thecontrol of the drive controller 41.

[0163] The system controller 18 waits for completion of the access atstep S2. On completion of the access, the system controller 18 at stepS3 waits for the optical head 22 to read the target reproduction startaddress. After confirming at step S4 that the optical head 22 hasreached the reproduction start address, the system controller 18 at stepS5 instructs the medium drive unit 11 to start data reading of onecluster of the next-generation MD clusters.

[0164] In response to this, the medium drive unit 11 starts data readingfrom the disc 90 under the control of the drive controller 41. Datareadout by the reproducing system including the optical head 22, the RFamplifier 24, the RLL(1-7)PP demodulator 35 and the RS-LDC decoder 36 isoutputted and supplied to the memory transfer controller 12.

[0165] At this point, the system controller 18 at step S6 judges whethersynchronization with the disc 90 is realized or not. If synchronizationwith the disc 90 is not realized, the system controller 18 at step S7generates a signal indicating occurrence of a data reading error. If itis determined at step S8 that reading is to be executed again, theprocesses from step S2 are repeated.

[0166] When the data of one cluster is acquired, the system controller18 at step S10 starts error correction of the acquired data. If theacquired data has an error at step S11, the system controller 18 returnsto step S7 to generate a signal indicating occurrence of a data readingerror. If the acquired data has no error, the system controller 18 atstep S12 judges whether a predetermined cluster has been acquired ornot. If the predetermined cluster has been acquired, the series ofprocessing ends and the system controller 18 waits for the medium driveunit 11 to complete the reading operation and causes the data read outand supplied to the memory transfer controller 12 to be stored into thecluster buffer memory 13. If the predetermined cluster has not beenacquired, the processes from step S6 are repeated.

[0167] The data of one cluster of the next-generation MD clusters readinto the cluster buffer memory 13 contains plural FAT sectors.Therefore, the data storage position of the requested FAT sector isfound from these, and the data of the one FAT sector (2048 bytes) issent to the external PC 100 from the USB interface 15. Specifically, thesystem controller 18 finds, from the requested FAT sector number #n,byte offset #b in the next-generation MD cluster containing this sector.Then, the system controller 18 causes the data of the one FAT sector(2048 bytes) from the position of byte offset #b in the cluster buffermemory 13 to be read out, and transfers the read-out data to the PC 100via the USB interface 15.

[0168] By the above-described processing, reading and transfer of anext-generation MD sector corresponding to a reading request for one FATsector from the PC 100 can be realized.

[0169] 6. Sector Writing Processing on Data Track

[0170] The processing in the system controller 18 of the disc drivedevice 10 in the case a writing request for a certain FAT sector is sentfrom the PC 100 will now be described with reference to FIG. 15.

[0171] When the system controller 18 receives a writing command for FATsector #n from the PC 100 via the USB interface 16, the systemcontroller 18 finds the next-generation MD cluster number of thenext-generation MD cluster containing the FAT sector of the designatedFAT sector number #n as described above.

[0172] As next-generation MD cluster number #u of the next-generation MDcluster containing FAT sector number #n is found, the system controller18 judges whether or not the next-generation MD cluster of the foundcluster number #u has already been read out from the disc 90 and storedin the cluster buffer memory 13. If not, the system controller 18performs processing to read out the next-generation MD cluster ofcluster number u from the disc 90. That is, the system controller 18instructs the medium drive unit 11 to read out the next-generation MDcluster of cluster number #u and to store the read-out next-generationMD cluster into the cluster buffer memory 13.

[0173] Moreover, the system controller 18 finds, from FAT sector number#n of the writing request, byte offset #b in the next-generation MDcluster containing this sector, in the above-described manner. Then, thesystem controller 18 receives data of 2048 bytes as writing data to theFAT sector (#n) transferred from the PC 100 via the USB interface 15,and start writing the data of one FAT sector (2048 bytes) at theposition of byte offset #b in the cluster buffer memory 13.

[0174] Therefore, of the data of the next-generation MD cluster (#u)stored in the cluster buffer memory 13, only the FAT sector (#n)designated by the PC 100 is rewritten. Thus, the system controller 18performs processing to write the next-generation MD cluster (#u) storedin the cluster buffer memory 13 to the disc 90. The processing up tothis point is a recording data preparation process of step S21. In thiscase, too, it is assumed that discrimination of the medium has alreadybeen completed by another technique.

[0175] Next, the system controller 18 at step S22 sets ADIP address #aof the recording start position from next-generation MD cluster number#u for writing. As ADIP address #a is set, the system controller 18instructs the medium drive unit 11 to access ADIP address #a. Therefore,the medium drive unit 11 executes access to ADIP address #a under thecontrol of the drive controller 41.

[0176] After confirming completion of the access at step S23, the systemcontroller 18 at step S24 waits for the optical head 22 to reach thetarget reproduction start address. As it is confirmed at step S25 thatthe optical head has reached the encode address of the data, the systemcontroller 18 at step S26 instructs the memory transfer controller 12 tostart transferring the data of the next-generation MD cluster (#u)stored in the cluster buffer memory 13 to the medium drive unit 11.

[0177] Then, after confirming at step S27 that the recording startaddress has been reached, the system controller 18 at step S28 instructsthe medium drive unit 11 to write the data of this next-generation MDcluster to the disc 90. In response to this, the medium drive unit 11starts data writing to the disc 90 under the control of the drivecontroller 41. That is, the data transferred from the memory transfercontroller 12 is recorded by the recording system including the RS-LDCencoder 47, the RLL(1-7)PP modulator 48, the magnetic head driver 46,the magnetic head 23 and the optical head 22.

[0178] At this point, the system controller 18 at step S29 judgeswhether synchronization with the disc 90 is realized or not. Ifsynchronization with the disc 90 is not realized, the system controller18 at step S30 generates a signal indicating occurrence of a datareading error. If it is judged at step S31 that reading is to beexecuted again, the processes from step S2 are repeated.

[0179] When data of one cluster is acquired, the system controller 18 atstep S32 judges whether a predetermined cluster has been acquired ornot. If the predetermined cluster has been acquired, the series ofprocessing ends.

[0180] By the above-described processing, writing of FAT sector data tothe disc 90 corresponding to a writing request for one FAT sector fromthe PC 100 can be realized. In short, writing of data by each FAT sectoris executed as rewriting of data by each next-generation MD cluster tothe disc 90.

[0181] 7. Relation Between ADIP Address and Address of Address Unit

[0182] The relation between the ADIP address and the address of theaddress unit will now be described with reference to FIGS. 16 and 17. Inthese FIGS. 16 and 17, AC represents the cluster address (clusternumber) based on the above-described ADIP, which is the physical addresson the disc, and AU represents the address of the above-describedaddress unit for accessing data. FIG. 16 shows the case of thenext-generation MD1. FIG. 17 shows the case of the next-generation MD2.

[0183] First, in FIG. 16, since the next-generation MD1 uses the ADIP ofthe conventional MD, 16 bits of AC0 to AC15 are used as the clusteraddresses (cluster number).

[0184] In FIG. 16, AC represents the cluster address and AD representsthe address sector. In consideration of a recording capacity ofapproximately 80 minutes as an actually used MD, it suffices to providea cluster address of approximately 12 bits. AC0 to AC14 of this ADIPcluster address are associated with address bits AU6 to AU20 of theaddress unit.

[0185] As the ADIP address of the conventional MD, a sector address of 8bits is arranged on the lower side of the cluster address. On the basisof this sector address, 0/1 expressing the sector address (FC to 0D) ofthe former-half cluster and the sector address (0E to 1F) of thelatter-half cluster shown in FIG. 9 is associated with address bit AU5of the address unit.

[0186] That is, this address bit AU5 has a value 0 in the case of theformer-half cluster (sectors FC to 0D) and 1 in the case of thelatter-half cluster (sectors 0E to 1F). This address bit AU5 of theaddress unit becomes the least significant bit of the address of theabove-described recording unit, and AU5 to AU20 represent the recordingblock number or recording block address. To a part 110 of 4 bits ofaddress bits AU4 to AU1 below address bit AU5, bits generated by a 4-bitcounter are allocated. That is, 4 bits for representing respective partsin the case where the above-described one recording block of FIG. 9 isequally divided by 16 are represented by address bits AU4 to AU1,respectively.

[0187] More specifically, the parts obtained equally dividing 496 framesof frame 10 to frame 505 as a data area, of 512 frames of one recordingblock of FIG. 9, by 16, are accessed with AU4 to AU1, respectively.

[0188] The least significant bit AU0 constantly has a value 0. In thisspecific embodiment, the number of bits of the address unit is 25, andthe value (code) of AC14 of the ADIP address is substituted into AU21 toAU23, which are above AU20. Alternatively, the value of AU20 of theaddress unit may be substituted into AU21 to AU23. Moreover, the value(code) of AC14 may be substituted into AU20, and the value (code) ofAC15 may be substituted into AU21 to AU23.

[0189] In consideration of a disc having plural recording areas forland/groove recording or two-spiral track recording, or a double-layerdisc, an address bit ABLG for identifying these recording areas isprovided. Thus, AU0 to AU23 and ABLG constitute an address of 25 bits.

[0190] In the leading three frames of 31 frames constituting addressunits obtained by equally dividing 496 frames of FIG. 9 by 16, theabove-described address unit number of 25 bits is recorded. This 25-bitaddress unit number may also be written into, for example, a part of theBIS area of FIG. 3 in a predetermined cycle (for example, a cycle of 31frames).

[0191]FIG. 20 shows the structure for realizing conversion from thecluster address to the unit address in the next-generation MD1. Thenumbers provided in FIG. 20 partly correspond to the numbers in FIG. 13.

[0192] The ADIP address demodulated by the ADIP demodulator 38 isconverted by the MD address demodulator 39 to an address of 20 bits intotal including cluster H, cluster L and sector. For the 16 bits (AC15to AC0) of cluster H and cluster L, an identifier is generated by aformer cluster/latter cluster identifier generator circuit 411 andregistered to AU5 by an address unit generator circuit 413.

[0193] Addresses generated for respective recording units by a recordingblock address generator circuit 412 are registered to AU1 to AU4 by theaddress unit generator circuit 413. The ADIP address demodulated by theADIP demodulator 38 is duplicated to AC8 to AC23 by the MD addressdemodulator 39, and cluster H and cluster L are partly duplicated to AC8to AC23 by the address unit generator circuit 413.

[0194] 0 is registered to AU0 and the address bit ABLG generated by theaddress unit generator circuit 413 is registered to AU25. The addressunit number generated by the address unit generator circuit 413 istransmitted to the data buffer 30, then modulated in a predeterminedmanner, and recorded for plural times into the leading three frames of31 frames constituting each address unit.

[0195] In the specific example shown in FIG. 16, a disc having onerecording area is used and ABLG is 0. However, in the case of a dischaving two recording areas, 1 or 0 is given in accordance with theindividual recording areas. In the case of a disc having three or morerecording areas, two or more address bits for identifying the recordingareas may be provided.

[0196] Next, in the case of the next-generation MD2 shown in FIG. 17,since an ADIP cluster includes 16 sectors, AC0 to AC15 of the clusteraddress (cluster number) of the ADIP address are associated with AU5 toAU20 of the address unit. Also in this case, address bit AU5 of theaddress unit becomes the least significant bit of the address of theabove-described recording unit, and AU5 to AU20 represent the recordingblock number or recording block address. To a part 110 of 4 bits ofaddress bits AU4 to AU1 below address bit AU5, bits generated by a 4-bitcounter are allocated. The least significant bit AU0 constantly has avalue 0. Moreover, the value (code) of AC15 of the ADIP address issubstituted into AU21 to AU23, which are above AU20.

[0197] Also in this specific example shown in FIG. 17, similar to thecase of FIG. 16, ABLG is constantly 0 corresponding to a disc having onerecording area. However, in the case of a disc having two recordingareas, 1 or 0 is given in accordance with the individual recordingareas. In the case of a disc having three or more recording areas, twoor more address bits for identifying the recording areas may beprovided.

[0198] The specific circuit in the case of FIG. 17 is the same as thatof FIG. 20 except for the former cluster/latter cluster identifiergenerator circuit 411, which is not provided in this case.

[0199] According to this embodiment of the present invention, thenext-generation DM1 enables data access using the 25-bit address (AU0 toAU25) extended for handling an increased data volume while using thesame physical address format as that of the conventional MD. Thenext-generation MD1 thus has excellent compatibility and enables accessto an increased volume of data without causing any inconvenience.Moreover, between the next-generation MD1 and the next-generation MD2,excellent data compatibility is realized as the 25 bit address (AU0 toAU25) of the address unit can be equally handled.

[0200] 8. Scrambling Processing for Each Sector (Logical Sector) of Data

[0201] Scrambling processing for each sector (logical sector) of datawill now be described with reference to FIGS. 18 and 19. In FIGS. 18 and19, AC represents the cluster address (cluster number) based on theabove-described ADIP, which is the physical address on the disc. AUrepresents the address of the address unit for accessing data, and srepresents each bit of a shift register for generating a pseudo-randomnumber. FIG. 18 shows the case of the next-generation MD1. FIG. 19 showsthe case of the next-generation MD2.

[0202] In the description of FIG. 2, 2052 bytes, obtained by adding 4byte EDC (error detection code) to every 2048 bytes of user datasupplied from a host application or the like, is handled as one sector(data sector or logical sector), and 32 sectors from sector 0 to sector31 are grouped as a block consisting of 304 columns and 216 rows. Fordata of 2052 bytes of each sector, a pseudo-random number is generatedusing the ADIP address as a seed or initial value of random number, andexclusive OR (EX-OR) with this pseudo-random number is taken to performscrambling processing. The pseudo-random number may be generated from,for example, a so-called maximum length sequence using a generatingpolynomial, and the seed of random number is loaded as an initial valueto a shift register for generating the maximum length sequence. The seedof random number may be, for example, the cluster address (clusternumber) of the ADIP address but it is not limited to this number.However, in the embodiment of the present invention, in consideration ofa disc having plural recording areas for land/groove recording ortwo-spiral track recording, or a double-layer disc, identificationinformation of these recording areas, for example, address bit ABLG forland/groove identification in FIGS. 18 and 19, may be used as a part ofthe seed of random number.

[0203] The data unit of 2048 bytes is called user data sector, and thedata unit of 2052 bytes with the EDC added thereto is called datasector.

[0204] Specifically, first, in the case of the next-generation MD1 shownin FIG. 18, AC0 to AC12 of the cluster address of ADIP are associatedwith AU6 to AU18 of the address unit. A high-order digit of the sectoraddress, which is 0 in the case of the former-half cluster (FC to 0D)and is 1 in the case of the latter-half cluster (0E to 1F), isassociated with AU5. The address bit ABLG for identifying the recordingareas of the disc having plural recording areas for land/grooverecording or the like is set at 0. These bits of AU5 to AU18 and ABLGare associated with 15 bits s0 to s14 from the lower side in the 16-bitshift register for generating a pseudo-random number. Considering that apseudo-random number cannot be generated if all the bits of the shiftregister become 0, 1 is associated with the most significant bit s15.The values of these bits AU5 to AU18 and ABLG and the value 1 for themost significant bit are loaded to the bits s0 to s15 of the 16 bitshift register every time the data sector of FIG. 2 starts. This is usedas an initial value and a pseudo-random number is generated. Then,exclusive OR (Ex-OR) of the generated pseudo-random number and each dataof the data sector is taken.

[0205] Next, in the case of the next-generation MD2 shown in FIG. 19,AC0 to AC13 of the cluster address of ADIP are associated with AU5 toAU18 of the address unit. The address bit ABLG for identifying therecording areas of the disc having plural recording areas forland/groove recording or the like is set at 0. These bits of AU5 to AU18and ABLG are associated with 15 bits s0 to s14 from the lower side inthe 16 bit shift register for generating a pseudo-random number.Considering that a pseudo-random number cannot be generated if all thebits of the shift register become 0, 1 is associated with the mostsignificant bit s15. The values of these bits AU5 to AU18 and ABLG andthe value 1 for the most significant bit are loaded to the bits s0 tosl5 of the 16 bit shift register every time the data sector of FIG. 2starts. This is used as an initial value and a pseudo-random number isgenerated. Then, exclusive OR (Ex-OR) of the generated pseudo-randomnumber and each data of the data sector is taken.

[0206] In the above-described specific examples, 16 bits obtained byconnecting the cluster address (recording block number), the address bitABLG for recording area identification and 1 of the most significantposition are uses as a seed of random number, and it is loaded as aninitial value to the 16 bit shift register for pseudo-random numbergeneration every time the data sector of FIG. 2 starts, thus generatinga pseudo-random number. However, the address is not limited to thecluster address (recording block number) and may include, for example, apart of the address below AU5. The timing at which the seed of randomnumber is loaded is not limited, either. In the case of a disc havingtwo recording areas, 1 or 0 is given in accordance with the individualrecording areas. In the case of a disc having three or more recordingareas, two or more address bits for identifying the recording areas maybe provided.

[0207] According to the embodiment of the present invention, asscrambling processing is performed to digital data in which a bias iseasily generated because of the regularity of the data or the like,randomness is realized and the recording/reproducing efficiency isimproved. Moreover, even in the case of a disc having plural recordingareas such as a land/groove recording disc or a multilayer disc and thushaving the same address on the neighboring tracks, since the seed forgeneration of random number differs between the recording areas, no samerandom number is generated and different scrambling processing isperformed. Therefore, interference between tracks can be reduced.

[0208] It should be understood by those ordinarily skilled in the artthat the invention is not limited to the above-described embodimentdescribed with reference to the drawings, but various modifications,alternative constructions or equivalents can be implemented withoutdeparting from the scope and spirit of the present invention as setforth and defined by the appended claims.

INDUSTRIAL APPLICABILITY

[0209] In the present invention, the word length of first addressinformation is set to be longer than the word length of second addressinformation and a part of the first address information is duplicated tothe second address information. An address is added to each high-densityblock and converted to the second address information. Thus, data can berecorded in plural recording formats to a recording medium on which thefirst address information is modulated in a predetermined manner andrecorded in advance, and a higher-density data volume can be handledwithout causing any inconvenience while using the existing recordingformat.

1. A disc recording/reproducing device adapted for, with respect to adisc on which a unit cluster having a predetermined number 2N (where Nis a positive integer) of sectors as a set is formed and on which asector address corresponding to each sector and a cluster addresscorresponding each cluster are modulated in a predetermined manner andrecorded in advance, performing recording and reproduction using Nsectors as a unit, which is obtained by bisecting the unit cluster, thedisc recording/reproducing device comprising: reproduction means forreproducing the cluster address and the sector address modulated in thepredetermined manner and recorded in advance, from the disc; identifiergeneration means for generating an identifier that identifies the formerN sectors or the latter N sectors obtained by bisecting the clusterunit, as a recording unit used for recording data; recording means forblocking inputted data into plural blocks and recording the blocked datawithin the N-sector recording unit; address generation means forgenerating an address corresponding to the plural blocks each that areformed in the N-sector recording unit; and conversion means forconverting the cluster address and the sector address reproduced by thereproducing means to an address unit including the identifier generatedby the identifier generation means, the address generated by the addressgeneration means and a recording block address generated on the basis ofthe cluster address; the address unit obtained by conversion by theconversion means being recorded for the plural blocks each, by therecording means.
 2. The disc recording/reproducing device as claimed inclaim 1, further comprising generation means for generating anidentifier that identifies a recording area when the disc has pluralrecording areas, wherein the identifier generated by the generationmeans is added to the address unit by the conversion means and thusrecorded.
 3. The disc recording/reproducing device as claimed in claim2, wherein the identifier generated by the generation means has a fixedvalue when the disc has a single recording area.
 4. A discrecording/reproducing device adapted for, with respect to a disc onwhich a unit cluster having a predetermined number 2N (where N is apositive integer) of sectors added to a linking sector longer than aninterleave length as a set is formed and on which a sector addresscorresponding to each sector and a cluster address corresponding eachcluster are modulated in a predetermined manner and recorded in advance,performing recording and reproduction using N sectors as a unit, whichis obtained by bisecting the unit cluster, the discrecording/reproducing device comprising: reproduction means forreproducing the cluster address and the sector address modulated in thepredetermined manner and recorded in advance, from the disc; recordingmeans for blocking inputted data into plural blocks and recording theblocked data within the N-sector recording unit; address generationmeans for generating an address corresponding to the plural blocks eachthat are formed in the N-sector recording unit; and conversion means forconverting the cluster address and the sector address reproduced by thereproducing means to an address unit including the address generated bythe address generation means and a recording block address generated onthe basis of the cluster address; the address unit obtained byconversion by the conversion means being recorded for the plural blockseach, by the recording means.
 5. The disc recording/reproducing deviceas claimed in claim 4, further comprising generation means forgenerating an identifier that identifies a recording area when the dischas plural recording areas, wherein the identifier generated by thegeneration means is added to the address unit by the conversion meansand thus recorded.
 6. The disc recording/reproducing device as claimedin claim 5, wherein the identifier generated by the generation means hasa fixed value when the disc has a single recording area.
 7. A discrecording/reproducing method adapted for, with respect to a disc onwhich a unit cluster having a predetermined number 2N (where N is apositive integer) of sectors as a set is formed and on which a sectoraddress corresponding to each sector and a cluster address correspondingeach cluster are modulated in a predetermined manner and recorded inadvance, performing recording and reproduction using N sectors as aunit, which is obtained by bisecting the unit cluster, the discrecording/reproducing method comprising: a step of reproducing thecluster address and the sector address modulated in the predeterminedmanner and recorded in advance, from the disc; a step of generating anidentifier that identifies the former N sectors or the latter N sectorsobtained by bisecting the cluster unit, as a recording unit used forrecording data; a step of generating an address corresponding to theplural blocks each that are formed in the N-sector recording unit; astep of converting the reproduced cluster address and sector address toan address unit including the generated identifier, the generatedaddress and a recording block address generated on the basis of thecluster address; and a step of blocking inputted data into pluralblocks, then recording the blocked data in the N-sector recording unit,and recording the address unit obtained by the conversion for the pluralblocks each.
 8. A disc recording/reproducing method adapted for, withrespect to a disc on which a unit cluster having a predetermined number2N (where N is a positive integer) of sectors added to a linking sectorlonger than an interleave length as a set is formed and on which asector address corresponding to each sector and a cluster addresscorresponding each cluster are modulated in a predetermined manner andrecorded in advance, performing recording and reproduction using Nsectors as a unit, which is obtained by bisecting the unit cluster, thedisc recording/reproducing method comprising: a step of reproducing thecluster address and the sector address modulated in the predeterminedmanner and recorded in advance, from the disc; a step of generating anaddress corresponding to the plural blocks each that are formed in theN-sector recording unit; a step of converting the reproduced clusteraddress and sector address to an address unit including the generatedaddress and a recording block address generated on the basis of thecluster address; and a step of blocking inputted data into pluralblocks, then recording the blocked data within the N-sector recordingunit, and recording the address unit obtained by the conversion for theplural blocks each.